Optical waveguide structure

Abstract

This optical waveguide structure is provided, for example, with: a first member having a first surface facing a first direction; and a waveguide layer having a core layer extending in a second direction intersecting the first direction at a position away from the first surface, a cladding layer surrounding the core layer on the first surface and having a protruding portion at least at a position on the opposite side from the first member with respect to the core layer, and an inclined portion extending in the second direction from the first surface. A protruding portion protruding in a first direction with respect to a peripheral portion thereof, the inclined portion being provided at a boundary between the protruding portion and the peripheral portion; a second member provided on a side opposite to the first member with respect to an end portion of the waveguide layer in the longitudinal direction; and an adhesive that joins the cladding layer and the second member at a position offset from the inclined portion.

Description

Technical Field

[0001] The invention relates to an optical waveguide structure. Background Art

[0002] As a conventional optical waveguide structure, the following technology is known: by adding a member to the optical waveguide structure at a connection portion with other members, the mechanical properties such as rigidity and strength of a subassembly formed by integrating the optical waveguide structure with other members are improved (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-214115 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The inventors have conducted intensive research on this type of optical waveguide structure and have found a structure that can further improve the mechanical properties of a subassembly that integrates the optical waveguide structure and other components.

[0008] Therefore, one of the objects of the present invention is to obtain an optical waveguide structure having a novel structure capable of further improving the mechanical properties of a subassembly in which the optical waveguide structure and other members are integrated, for example.

[0009] Solutions to Solve Problems

[0010] The optical waveguide structure of the present invention comprises, for example: a first member having a first surface facing a first direction; a waveguide layer having a core layer, a cladding layer, and an inclined portion, wherein the core layer extends in a second direction intersecting the first direction at a position away from the first surface, the cladding layer surrounds the core layer on the first surface, and has a protrusion at least at a position on the opposite side of the core layer to the first member, the protrusion protruding in the first direction relative to its peripheral portion, and the inclined portion is provided at a boundary between the protrusion and the peripheral portion; a second member provided on the opposite side of the first member relative to the end portion of the waveguide layer in the longitudinal direction; and an adhesive bonding the cladding layer to the second member at a position deviated from the inclined portion.

[0011] In the optical waveguide structure, the waveguide layer may include a first adhesive for bonding the protruding portion and the second member as the adhesive.

[0012] In the optical waveguide structure, the waveguide layer may include a second adhesive for bonding the peripheral portion and the second member as the adhesive.

[0013] In the optical waveguide structure, the waveguide layer may include a first adhesive and a second adhesive as the adhesive, the first adhesive bonding the protruding portion to the second member, and the second adhesive bonding the peripheral portion to the second member.

[0014] In the optical waveguide structure, the waveguide layer may include a plurality of adhesives for bonding the cladding layer and the second member as the adhesive.

[0015] In the optical waveguide structure, the inclined portion may be located between the plurality of adhesives.

[0016] In the optical waveguide structure, a plurality of inclined portions may be located between the plurality of adhesives as the inclined portions.

[0017] In the optical waveguide structure, the cladding layer may also have a first inclined portion and a second inclined portion as the inclined portion, the first inclined portion being located at an end portion of the protrusion in a third direction intersecting the first direction and the second direction, the second inclined portion being located at an end portion of the protrusion in a direction opposite to the third direction, and the first inclined portion and the second inclined portion being located between the plurality of adhesives.

[0018] In the optical waveguide structure, the waveguide layer may include a dummy layer arranged at a distance from the core layer in a direction intersecting the first direction and the second direction, and the protrusion may include a portion located on the opposite side of the dummy layer from the first member.

[0019] In the optical waveguide structure, the waveguide layer may include a first dummy layer and a second dummy layer as the dummy layers, wherein the first dummy layer is deviated from the core layer in a third direction intersecting the first direction and the second direction, and the second dummy layer is deviated from the core layer in a direction opposite to the third direction.

[0020] In the optical waveguide structure, the dummy layer may include a leakage portion through which light leaks.

[0021] In the optical waveguide structure, the dummy layer may be provided with a shape that is a concave portion or a convex portion as the leakage portion at an edge portion of the dummy layer on the side opposite to the core layer when viewed in a direction opposite to the first direction.

[0022] In the optical waveguide structure, the thickness of the cladding layer stacked on the core layer in the first direction may be 15 [μm] or less.

[0023] In the optical waveguide structure, the cladding layer may include tetraethoxysilane.

[0024] In the optical waveguide structure, the width of the core layer in a third direction intersecting the first direction and the second direction may be 1 [mm] or more.

[0025] Effects of the Invention

[0026] According to the present invention, it is possible to obtain an optical waveguide structure having a novel structure that can further improve the mechanical properties of a subassembly in which the optical waveguide structure and other members are integrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is an illustrative and schematic side view of the optical waveguide structure of the first embodiment.

[0028] Figure 2 This is an illustrative and schematic front view of a part of the optical waveguide structure according to the first embodiment.

[0029] Figure 3 It is an illustrative and schematic top view of the optical waveguide structure of the first embodiment.

[0030] Figure 4 This is an illustrative and schematic front view of a part of the optical waveguide structure of the second embodiment.

[0031] Figure 5 This is an illustrative and schematic front view of a part of the optical waveguide structure according to the third embodiment.

[0032] Figure 6 This is an illustrative and schematic front view of a part of the optical waveguide structure according to the fourth embodiment.

[0033] Figure 7 This is an illustrative and schematic front view of a part of the optical waveguide structure of the fifth embodiment.

[0034] Figure 8 yes Figure 7 VIII-VIII sectional view of the invention.

[0035] Fig. 9 FIG. 1 is an illustrative and schematic plan view of a waveguide layer of the optical waveguide structure according to the fifth embodiment.

[0036] Fig.10This is an illustrative and schematic front view of a part of the optical waveguide structure of the sixth embodiment.

[0037] Fig.11 This is an illustrative and schematic front view of a part of the optical waveguide structure of the seventh embodiment.

[0038] Fig.12 This is an illustrative and schematic front view of a part of the optical waveguide structure of the eighth embodiment.

[0039] Fig.13 This is an illustrative and schematic front view of a part of the optical waveguide structure of the ninth embodiment. DETAILED DESCRIPTION

[0040] The following discloses an exemplary embodiment of the present invention. The structure of the embodiment shown below and the action and result (effect) brought about by the structure are examples. The present invention can also be implemented by a structure other than the structure disclosed in the following embodiment. In addition, according to the present invention, at least one of the various effects (including derived effects) obtained by the structure can be obtained.

[0041] The multiple embodiments shown below have the same structure. Therefore, according to the structure of each embodiment, the same action and effect obtained based on the same structure can be obtained. In addition, the same reference numerals are sometimes used to mark these same structures below, and repeated descriptions are omitted.

[0042] In this specification, numbers are given for the convenience of distinguishing parts, directions, locations, components, etc., and do not indicate priority or order, nor do they specify the number.

[0043] In each figure, the X direction is indicated by an arrow X, the Y direction is indicated by an arrow Y, and the Z direction is indicated by an arrow Z. The X direction, the Y direction, and the Z direction intersect and are orthogonal to each other. It should be noted that, hereinafter, the X direction is also referred to as the long side direction or the extension direction, the Y direction is referred to as the short side direction or the width direction, and the Z direction is referred to as the stacking direction or the height direction.

[0044] In addition, each figure is a schematic diagram for the purpose of explanation, and the scale and ratio in each figure are not necessarily the same as the actual object.

[0045] [First embodiment]

[0046] Figure 1 FIG. 1 is a side view of the optical waveguide structure 100A ( 100 ) according to the first embodiment. Figure 1As shown, the optical waveguide structure 100 includes a base 10, a waveguide layer 20A (20), a member 30A (30), and an adhesive 40. The base 10, the waveguide layer 20, the adhesive 40, and the member 30 are stacked in the Z direction. The member 30 is provided on the side opposite to the base 10 with respect to the end 20e of the waveguide layer 20 in the X direction, that is, the end 20e in the long side direction. The adhesive 40 bonds the end 20e of the waveguide layer 20 to the member 30. The base 10 is an example of a first member. The adhesive 40 may also be referred to as a bonding agent. The base 10 may also be referred to as a substrate. In addition, the base 10 and the waveguide layer 20 constitute a PLC (planar lightwave circuit).

[0047] like Figure 1 As shown, the end face 100e of the optical waveguide structure 100 and the end face 200e of another optical structure 200 are bonded in a state facing each other by using an adhesive or the like, thereby the optical waveguide structure 100 and the optical structure 200 are integrated. The end face 100e is constituted by the end face of the base 10, the waveguide layer 20, the adhesive 40 and the component 30. The end face 20e1 of the waveguide layer 20 located inside the end face 100e of the optical waveguide structure 100 is the input end or output end of the light. In addition, the optical structure 200 is, for example, an optical fiber support structure or an optical sensor, etc., but is not limited thereto. In the subassembly of the optical waveguide structure 100 and the optical structure 200, the waveguide layer 20 of the optical waveguide structure 100 is optically connected to the waveguide (not shown) of the optical structure 200.

[0048] Here, assuming that the optical waveguide structure 100 does not include the component 30 and the adhesive 40 but only includes the base 10 and the waveguide layer 20, the thickness in the Z direction becomes thinner than the structure including the component 30 and the adhesive 40. Therefore, the subassembly of the optical waveguide structure 100 and the optical structure 200 may be easily bent and broken at the joint portion of the end faces 100e and 200e. In addition, the end face 100e is narrow, and accordingly, the tensile strength may be insufficient. In this regard, the optical waveguide structure 100 of the present embodiment includes the component 30 and the adhesive 40 facing the optical structure 200 on the side opposite to the base 10 with respect to the end 20e of the waveguide layer 20. Therefore, compared with the structure without the component 30 and the adhesive 40, it is easy to improve the mechanical properties such as bending rigidity, bending strength, shear strength, and tensile strength of the subassembly formed by integrating the optical waveguide structure 100 and the optical structure 200. The component 30 is an example of the second component. The member 30 functions as a reinforcing member, and may also be referred to as an upper plate, a fixing member, or the like.

[0049] Figure 2 FIG. 1 is a front view of a portion of the end surface 100e of the optical waveguide structure 100A and (100) of the first embodiment. The base 10 is, for example, a silicon substrate. Figure 1 , 2 As shown, the base 10 intersects and is orthogonal to the Z direction, and extends in the X direction and the Y direction. The base 10 has a surface 10a. The surface 10a is an end surface in the Z direction. The surface 10a faces the Z direction, intersects and is orthogonal to the Z direction, and extends in the X direction and the Y direction. The Z direction is an example of a first direction. The surface 10a is an example of a first surface.

[0050] like Figure 2 As shown, the waveguide layer 20 includes a first cladding layer 21, a core layer 22, and a second cladding layer 23. The first cladding layer 21, the core layer 22, and the second cladding layer 23 are stacked in this order on the surface 10a by CVD (chemical vapor deposition).

[0051] The first coating layer 21 covers the surface 10a of the base 10 with a thickness t1 that is substantially constant in the Z direction. The first coating layer 21 crosses and is orthogonal to the Z direction, and extends in the X direction and the Y direction.

[0052] The core layer 22 is stacked on a portion of the upper surface 21a of the first cladding layer 21 with a thickness t2 that is substantially constant in the Z direction. In other words, the first cladding layer 21 is sandwiched between the core layer 22 and the surface 10a of the base 10. That is, the core layer 22 is arranged so as to be away from the surface 10a in the Z direction. In addition, at the end 20e of the waveguide layer 20, the core layer 22 extends in the X direction with a predetermined width w1. The X direction is an example of the second direction.

[0053] The second cladding layer 23 is stacked on the first cladding layer 21 and the core layer 22 with a thickness t3 that is substantially constant in the Z direction. Figure 2It can be seen that the core layer 22 is stacked on the upper surface 21a of the first cladding layer 21. Therefore, in the state before the second cladding layer 23 is stacked, the core layer 22 protrudes from the upper surface 21a in the Z direction with a thickness t2. Therefore, the second cladding layer 23 stacked on the first cladding layer 21 and the core layer 22 in such a shape and configuration includes a portion 23a formed on the upper surface 21a away from the core layer 22 and a portion 23b formed on the core layer 22, and a protrusion 23p is formed in the portion on the opposite side of the base 10 relative to the core layer 22. The protrusion 23p is a part of the portion 23b (the end portion in the Z direction). Here, the top surface 23p1 of the protrusion 23p, that is, the top surface 23p1 located at the end portion of the portion 23b in the Z direction faces the Z direction, intersects and is orthogonal to the Z direction, and extends in the X direction and the Y direction. In addition, the surface 23a1 located at the end of the portion 23a in the Z direction also faces the Z direction, intersects and is orthogonal to the Z direction, and extends in the X direction and the Y direction. In addition, the top surface 23p1 protrudes in the Z direction relative to the surface 23a1 at a height substantially the same as the thickness t2 of the core layer 22. The surface 23a1 is an example of a peripheral portion relative to the protruding portion 23p, and may also be referred to as a base surface or a flat surface.

[0054] In such a structure, the first cladding layer 21 and the second cladding layer 23 constitute cladding layers that surround the core layer 22 on the surface 10 a of the susceptor 10 and extend in the X direction.

[0055] The cladding layers, i.e., the first cladding layer 21 and the second cladding layer 23, are made of, for example, a quartz glass material. The core layer 22 is made of, for example, a quartz glass material having a higher refractive index than the first cladding layer 21 and the second cladding layer 23. The core layer 22 may also be made of, for example, quartz glass containing germanium (GeO2) or zirconium oxide (ZrO2) as a dopant for increasing the refractive index. The member 30 is made of, for example, a quartz glass material or a borosilicate glass material. In addition, the adhesive 40 is made of, for example, an epoxy resin, an acrylic resin, a vinyl resin, or the like.

[0056] In such a structure, an inclined portion 23i is formed at the boundary between the protrusion 23p and the surface 23a1. The inclined portion 23i includes an inclined portion 23i1 located at the end of the protrusion 23p in the Y direction and an inclined portion 23i2 located at the end of the protrusion 23p in the opposite direction to the Y direction. The inclined portion 23i1 is an example of a first inclined portion, and the inclined portion 23i2 is an example of a second inclined portion. The Y direction is an example of a third direction.

[0057] Figure 3 1 is a top view of the optical waveguide structure 100A (100) of the first embodiment. As described above, the protrusion 23p is formed on the side opposite to the base 10 with respect to the core layer 22. Therefore, Figure 3 The planar shape of the protrusion 23p shown in FIG. 2 roughly represents the planar shape of the core layer 22. Figure 3 In the example, the protrusion 23p extends in the X direction, and the width of the protrusion 23p in the Y direction changes. That is, the core layer 22 extends in the X direction, and the width of the core layer 22 in the Y direction changes. In addition, the protrusion 23p has a section where the width in the Y direction becomes wider as it approaches the X direction, and the width in the Y direction at the end of the protrusion 23p in the X direction is wider than the width in the Y direction at the end of the protrusion 23p in the opposite direction of the X direction. That is, the core layer 22 has a section where the width in the Y direction becomes wider as it approaches the X direction, and the width in the Y direction at the end of the core layer 22 in the X direction is wider than the width in the Y direction at the end of the core layer 22 in the opposite direction of the X direction. It should be noted that the planar shape of the protrusion 23p, that is, the planar shape of the core layer 22 is not limited to. Figure 3 , for example, it can be of constant width, or it can be branched or curved.

[0058] In the above structure, when the relative refractive index difference between the core layer 22 and the first cladding layer 21 and the second cladding layer 23 is set to a high value such as 5 [%], the light confinement effect at the core layer 22 is improved, so the first cladding layer 21 and the second cladding layer 23 can be further thinned. In this case, the thickness t1 and t3 of the first cladding layer 21 and the second cladding layer 23 can be reduced (see Figure 2 ) is set to, for example, 10 [μm], and the thickness t2 of the core layer 22 (refer to Figure 2 ) is set to, for example, 3 [μm]. In addition, the width w1 of the core layer 22 (see Figure 2 ) is set to, for example, 1 [mm] or more.

[0059] The inventors have found through experimental studies that when the thickness t3 of the second cladding layer 23 is thinner as in the above-mentioned structure, the inclination of the inclined portion 23i relative to the surface 23a1 and the top surface 23p1 becomes steeper than when it is thicker. It is presumed that this is because, when laminating the second cladding layer 23 based on the CVD method, when the thickness t3 of the second cladding layer 23 is thicker, the effect of slowing down the inclination of the inclined portion 23i corresponding to the inclination of the end edge in the width direction of the core layer 22 can be obtained, whereas when the thickness t3 is thinner, it is difficult to obtain the effect of slowing down the inclination, and the inclined portion 23i becomes steeper. In addition, the inventors have found that when a fluid, pre-cured adhesive 40 is applied to such a steep inclined portion 23i, the adhesive 40 does not enter the corner C between the inclined portion 23i and the surface 23a1 (see Figure 2), and a gap is generated between the corner C and the adhesive 40, and the bonding strength of the waveguide layer 20 and the member 30 by the adhesive 40 may be reduced, and individual differences in bonding strength may occur. When the bonding strength of the waveguide layer 20 and the member 30 is reduced, the bonding strength of the optical waveguide structure 100 and the optical structure 200 is also reduced, and further, the mechanical properties of the subassembly of the optical waveguide structure 100 and the optical structure 200 are also impaired.

[0060] Therefore, in this embodiment, the adhesive 40 is not applied to the inclined portion 23i, but the waveguide layer 20 (second cladding layer 23) and the component 30 are joined at a position deviated from the inclined portion 23i, especially the corner C between the inclined portion 23i and the surface 23a1, that is, the root of the protrusion 23p, in other words, a position away from the corner C.

[0061] exist Figure 2 In the example of FIG. 1 , the adhesive 40 is provided on the top surface 23 p 1 of the protrusion 23 p , and the top surface 23 p 1 is bonded to the bottom surface 30 a of the member 30 .

[0062] According to such a configuration, it is possible to suppress a situation where the required bonding strength cannot be obtained due to the adhesive 40 not entering the corner portion C, and it is possible to suppress the occurrence of individual differences in the bonding strength due to the adhesive 40 .

[0063] The structure in which the member 30A is located on the protruding portion 23 p as in the present embodiment is more effective when the width w1 of one core layer 22 is as wide as 1 [mm] or more.

[0064] It should be noted that the fact that the second cladding layer 23 contains tetraethoxysilane can confirm that the second cladding layer 23 is laminated by the CVD method that produces the steep slope portion 23 i described above.

[0065] In addition, the inventors have found through research that the steeply inclined portion 23i which makes it difficult for the adhesive 40 to enter the corner C is easily formed when the thickness t3 of the second cladding layer 23 is thin, for example, 15 [μm] or less. That is, the structure of the present embodiment is more effective when the thickness t3 of the second cladding layer 23 is 15 [μm] or less.

[0066] [Second embodiment]

[0067] Figure 4 FIG. 1 is a front view of an optical waveguide structure 100B ( 100 ) according to the second embodiment. Figure 4 and Figure 2 As can be seen from the comparison, the shape of the member 30B ( 30 ) is different from that of the member 30A ( 30 ) of the first embodiment.

[0068] In the present embodiment, the width of the member 30B in the Y direction at a position away from the bonding portion bonded to the adhesive 40 in the Z direction is wider than the width of the bonding portion in the Y direction. According to the present embodiment, the area of ​​the end face 100e bonded to the end face 200e of another optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved.

[0069] [Third embodiment]

[0070] Figure 5 1 is a front view of an optical waveguide structure 100C (100) according to the third embodiment. In the present embodiment, the member 30C (30) and the waveguide layer 20 are bonded by an adhesive 40 provided at a plurality of locations (two locations in this example). The adhesive 40 includes an adhesive 40a that bonds the protrusion 23p to the member 30C, and an adhesive 40b that bonds the surface 23a1 to the member 30C at a position that is offset from the inclined portion 23i and away from the corner C. In this case, the inclined portion 23i is located between the plurality of adhesives 40a and 40b. The adhesive 40a is an example of a first adhesive, and the adhesive 40b is an example of a second adhesive.

[0071] According to the present embodiment, the adhesive 40 is provided at two locations, and accordingly, the bonding strength between the member 30C and the waveguide layer 20 can be further improved. In addition, since the adhesive 40 is provided at two locations separated in the Y direction, the member 30C has a wider width in the Y direction, and therefore, the area of ​​the end face 100e bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved.

[0072] [Fourth embodiment]

[0073] Figure 6 : is a front view of the optical waveguide structure 100D (100) of the fourth embodiment. In this embodiment, the member 30D (30) and the waveguide layer 20 are also joined by the adhesive 40 provided at multiple locations (three locations in this example). The adhesive 40 includes: an adhesive 40a that joins the protrusion 23p to the member 30D; and two adhesives 40b that join the surface 23a1 to the member 30C at a position deviated from the inclined portion 23i and away from the corner C. In addition, in this embodiment, the two inclined portions 23i1 and 23i2 are located between the two adhesives 40b.

[0074] According to the present embodiment, the adhesive 40 is provided at three locations, and accordingly, the bonding strength between the member 30C and the waveguide layer 20 can be further improved. In addition, since the adhesive 40 is provided at three locations separated in the Y direction, the member 30C has a wider width in the Y direction, and therefore, the area of ​​the end face 100e bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved.

[0075] [Fifth Embodiment]

[0076] Figure 7 This is a front view of an optical waveguide structure 100E ( 100 ) according to the fifth embodiment. The waveguide layer 20E ( 20 ) of this embodiment is provided with dummy layers 24A and 24B ( 24 ) arranged in parallel with the core layer 22 in the Y direction.

[0077] The dummy layer 24 is laminated in the same process as the core layer 22. The dummy layer 24 is made of the same composition as the core layer 22 and has the same thickness t2 as the core layer 22 (see Figure 2 ). In addition, the second cladding layer 23 is sandwiched between the dummy layer 24 and the core layer 22. Therefore, light is not easily leaked from the core layer 22 to the dummy layer 24. It should be noted that the dummy layer 24A deviated in the Y direction relative to the core layer 22 is an example of a first dummy layer, and the dummy layer 24B deviated in the opposite direction of the Y direction relative to the core layer 22 is an example of a second dummy layer.

[0078] according to Figure 7 It can be seen that, in this case, the protrusion 23p is formed so as to cover the core layer 22 and the two dummy layers 24. That is, the protrusion 23p includes a portion located on the opposite side of the dummy layer 24 from the base 10.

[0079] With such a structure, the width of the protrusion 23p in the Y direction can be further widened. In this case, the width of the adhesive 40 in the Y direction can be widened, and accordingly, the bonding strength of the protrusion 23p and the member 30E can be improved. In addition, the width of the protrusion 23p and the adhesive 40 is widened, and accordingly, the member 30E has a wider width in the Y direction, so the area of ​​the end face 100e that is bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength of the optical structure 200 can be improved.

[0080] It should be noted that a groove 23g is formed in the top surface 23p1 at a position parallel to the interval between the core layer 22 and the dummy layer 24 in the Z direction. The depth of the groove 23g is set to be shallower than the height of the protruding portion 23p, that is, the thickness t2 of the core layer 22, and to a degree that the adhesive 40 can enter. Therefore, it is possible to avoid the following situation: the adhesive 40 does not enter the groove 23g, and a gap is generated between the adhesive 40 and the protruding portion 23p, and the bonding strength of the waveguide layer 20 and the member 30E by the adhesive 40 is reduced.

[0081] Figure 8 yes Figure 7 VIII-VIII cross-sectional view of FIG. If the cross-sectional view is observed in the opposite direction of the Z direction, Figure 8 As shown in FIG. 1 , a concave shape 24b and a convex shape 24a are provided at the edge of the dummy layer 24 on the side opposite to the core layer 22. Figure 8 In a top view, the concave shape 24b and the convex shape 24a are formed by alternately arranging the edge extending in the X direction and the edge extending in the Y direction. Assuming that light leaks from the core layer 22 to the dummy layer 24, it is not preferable that the leaked light is transmitted in the dummy layer 24 toward the optical structure 200 along the X direction. Therefore, in the present embodiment, the concave shape 24b and the convex shape 24a are provided at the position of the dummy layer 24 in the waveguide layer 20 so that the effective refractive index changes discontinuously along the X direction. With such a structure, the light transmitted in the dummy layer 24 leaks from the concave shape 24b and the convex shape 24a to the outside of the dummy layer 24. As an example, the width w2 of the convex shape 24a in the Y direction is 500 [μm], and the width w3 of the concave shape 24b in the Y direction is 250 [μm]. The length L1 of the convex shape 24a in the X direction is 300 [μm] or more and 2000 [μm] or less, and the length L2 of the concave shape 24b in the X direction is 200 [μm] or more and 1000 [μm] or less. In addition, the distance d1 between the core layer 22 and the dummy layer 24 is 10 [μm]. The values ​​of the width w2, width w3, length L1, length L2, and distance d1 are just examples and are not limited to the above values. The concave shape 24b and the convex shape 24a are examples of leakage parts.

[0082] It should be noted that the optical waveguide structure 100E of the present embodiment has a structure that is plane-symmetrical with respect to the imaginary plane VP. The imaginary plane VP is along the X direction and the Z direction and is orthogonal to the Y direction. Therefore, the dummy layer 24B also has a structure that is plane-symmetrical with respect to the dummy layer 24A. Therefore, the dummy layer 24B can also obtain the same effect as the dummy layer 24A.

[0083] Fig. 9is a top view of the waveguide layer 20E of the optical waveguide structure 100E, in other words, a top view showing the state before the component 30E is placed on the waveguide layer 20E in the manufacturing process of the optical waveguide structure 100E. In the present embodiment, a protrusion 23p corresponding to the core layer 22 and the dummy layer 24 is formed at the end of the waveguide layer 20 in the Z direction. That is, when viewed from above in the direction opposite to the Z direction, the protrusion 23p has a shape corresponding to the concave shape 24b and the convex shape 24a. That is, the inclined portion 23i1 located at the end of the protrusion 23p in the Y direction and the inclined portion 23i2 located at the end in the direction opposite to the Y direction respectively have a section 23ia extending in the X direction and a section 23ib extending in the Y direction. In this case, as Fig. 9 As shown, when the member 30E is placed on the waveguide layer 20, the sections 23ia and 23ib can be used to position the member 30E. That is, the sections 23ia and 23ib of the inclined portion 23i are examples of alignment marks.

[0084] [Sixth embodiment]

[0085] Fig.10 1 is a front view of an optical waveguide structure 100F (100) according to the sixth embodiment. In this embodiment, the member 30F (30) and the waveguide layer 20 are also bonded by an adhesive 40 provided at a plurality of locations (two locations in this example). The adhesive 40 includes two adhesives 40b that bond the surface 23a1 and the member 30F at a position that is offset from the inclined portion 23i and away from the corner C. In addition, in this embodiment, the two inclined portions 23i1 and 23i2 are located between the two adhesives 40b.

[0086] According to the present embodiment, the adhesive 40 is provided at two locations, and accordingly, the bonding strength between the component 30F and the waveguide layer 20 can be further improved. In addition, the adhesive 40 is provided at two locations separated in the Y direction, and accordingly, the component 30F has a wider width in the Y direction, so that the area of ​​the end face 100e that is bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength between the component 30F and the waveguide layer 20 can be improved. It should be noted that according to Fig.10 As can be seen from the example, it is not necessary to bond the member 30F ( 30 ) and the protrusion 23 p using the adhesive 40 .

[0087] [Seventh embodiment]

[0088] Fig.111 is a front view of an optical waveguide structure 100G (100) according to the seventh embodiment. In this embodiment, the member 30G (30) and the waveguide layer 20G (20) are also bonded by an adhesive 40 provided at a plurality of locations (two locations in this example). The adhesive 40 includes two adhesives 40b that bond the surface 23a1 to the member 30G at a position that is offset from the inclined portion 23i and away from the corner C. In addition, in this embodiment, the two protrusions 23p, that is, the four inclined portions 23i, are located between the two adhesives 40b.

[0089] According to the present embodiment, the adhesive 40 is provided at two locations, and accordingly, the bonding strength between the member 30G and the waveguide layer 20 can be further improved. In addition, since the adhesive 40 is provided at two locations separated in the Y direction, the member 30G has a wider width in the Y direction, and therefore, the area of ​​the end face 100e bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved. In addition, in the present embodiment, one member 30G functions as a reinforcing member corresponding to the plurality of protrusions 23p (core layer 22). In this case, compared with a structure in which the member 30 is provided separately for each of the plurality of protrusions 23p (core layer 22), the number of components can be further reduced, and further, the advantage of being able to suppress the workload and cost of manufacturing can be obtained.

[0090] [Eighth Embodiment]

[0091] Fig.12 1 is a front view of an optical waveguide structure 100H (100) according to the eighth embodiment. In this embodiment, the member 30H (30) and the waveguide layer 20 are also bonded by an adhesive 40 provided at a plurality of locations (two locations in this example). The adhesive 40 includes an adhesive 40a that bonds the protrusion 23p to the member 30H, and two adhesives 40b that bond the surface 23a1 to the member 30H at a position that is offset from the inclined portion 23i and away from the corner C. In addition, in this embodiment, the three inclined portions 23i are located between the two adhesives 40a and 40b.

[0092] According to the present embodiment, the adhesive 40 is provided at two locations, and accordingly, the bonding strength between the member 30H and the waveguide layer 20 can be further improved. In addition, since the adhesive 40 is provided at two locations separated in the Y direction, the member 30H has a wider width in the Y direction, and therefore, the area of ​​the end surface 100e bonded to the end surface 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved. In addition, in the present embodiment, one member 30H is also shared by a plurality of protrusions 23p (core layer 22), so the number of components can be further reduced, and the workload and cost of manufacturing can be suppressed.

[0093] [Ninth embodiment]

[0094] Fig.13 1 is a front view of an optical waveguide structure 100I (100) according to a ninth embodiment. In this embodiment, a member 30I (30) and a waveguide layer 20 are bonded by an adhesive 40 provided at a plurality of locations (two or more locations in this example). The adhesive 40 includes a plurality of adhesives 40a for bonding a protrusion 23p to the member 30I. In addition, in this embodiment, two inclined portions 23i are located between two adhesives 40a adjacent to each other in the Y direction. The member 30I is provided so as to cover two or more protrusions 23p.

[0095] According to the present embodiment, the adhesive 40 is provided at two or more locations, and accordingly, the bonding strength between the member 30I and the waveguide layer 20 can be further improved. In addition, the adhesive 40 is provided at two or more locations separated in the Y direction, and accordingly, the member 30I has a wider width in the Y direction, so the area of ​​the end face 100e bonded to the end face 200e of the optical structure 200 can be further increased, and accordingly, the bonding strength with the optical structure 200 can be improved. In addition, in the present embodiment, one member 30I is also shared by a plurality of protrusions 23p (core layer 22), so the number of components can be further reduced, and the workload and cost of manufacturing can be suppressed.

[0096] As described in the above-mentioned embodiments, the positions of the plurality of adhesives 40 may be in various combinations.

[0097] The above examples illustrate the embodiments and variations of the present invention, but the above embodiments and variations are examples and are not intended to limit the scope of the invention. The above embodiments and variations can be implemented in various other ways, and can be omitted, replaced, combined, and changed in various ways without departing from the scope of the invention. In addition, the specifications of various structures, shapes, etc. (structure, type, direction, model, size, length, width, thickness, height, quantity, configuration, position, material, etc.) can be appropriately changed for implementation.

[0098] For example, in the above-mentioned embodiment, the optical waveguide structure is a PLC, but the present invention is not limited thereto, and the optical waveguide structure may be, for example, a SiPh waveguide, an InP waveguide, or a SiN waveguide.

[0099] Industrial Applicability

[0100] The present invention can be used in an optical waveguide structure.

[0101] Description of Reference Numerals

[0102] 10…Base

[0103] 10a…Surface

[0104] 20, 20A, 20E, 20G… waveguide layer

[0105] 20e…end

[0106] 20e1…end face

[0107] 21…First coating layer

[0108] 21a…upper surface

[0109] 22…Core layer

[0110] 23…Second coating layer

[0111] 23a…part

[0112] 23b…

[0113] 23a1…Surface (peripheral part)

[0114] 23g...Slot

[0115] 23i…Inclined part

[0116] 23i1… inclined portion (first inclined portion)

[0117] 23i2… inclined portion (second inclined portion)

[0118] 23ia…Interval

[0119] 23ib…interval

[0120] 23p…protrusion

[0121] 23p1…top surface

[0122] 24…Dummy layer

[0123] 24A…Dummy layer (first dummy layer)

[0124] 24B…Dummy layer (second dummy layer)

[0125] 24a…Protrusion shape (leakage part)

[0126] 24b…Concave shape (leakage part)

[0127] 30, 30A~30I…Components

[0128] 30a…bottom

[0129] 40…Adhesive

[0130] 40a…adhesive (first adhesive)

[0131] 40b…adhesive (second adhesive)

[0132] 100, 100A~100I…Optical waveguide structure

[0133] 100e…end face

[0134] 200…Optical structure

[0135] 200e…end face

[0136] C…Corner

[0137] d1…distance

[0138] L1…Length

[0139] L2…Length

[0140] t1…Thickness

[0141] t2…Thickness

[0142] t3…Thickness

[0143] w1…width

[0144] w2…width

[0145] w3…width

[0146] VP…Imaginary Plane

[0147] X…direction (second direction)

[0148] Y…direction (third direction)

[0149] Z…direction (first direction).

Claims

1. An optical waveguide structure, comprising: A first member having a first surface facing a first direction; a waveguide layer comprising a core layer, a cladding layer, and an inclined portion, wherein the core layer extends in a second direction intersecting the first direction at a position away from the first surface, the cladding layer surrounds the core layer on the first surface, and has a protruding portion at least at a portion on the opposite side of the core layer to the first member, the protruding portion protruding in the first direction relative to the peripheral portion thereof, and the inclined portion is provided at a boundary between the protruding portion and the peripheral portion; a second member provided on a side opposite to the first member with respect to an end portion in the longitudinal direction of the waveguide layer; as well as An adhesive bonds the coating layer and the second member at a position offset from the inclined portion.

2. The optical waveguide structure according to claim 1, wherein: The waveguide layer includes a first adhesive as the adhesive for bonding the protruding portion and the second member.

3. The optical waveguide structure according to claim 1, wherein: The waveguide layer includes a second adhesive as the adhesive for bonding the peripheral portion to the second member.

4. The optical waveguide structure according to claim 1, wherein: The waveguide layer includes a first adhesive and a second adhesive as the adhesive, the first adhesive bonding the protruding portion to the second member, and the second adhesive bonding the peripheral portion to the second member.

5. The optical waveguide structure according to claim 1, wherein: The waveguide layer includes a plurality of adhesives as the adhesive for bonding the cladding layer and the second member.

6. The optical waveguide structure according to claim 5, wherein: The inclined portion is located between the plurality of adhesives.

7. The optical waveguide structure according to claim 5, wherein: A plurality of inclined portions are located between the plurality of adhesives as the inclined portions.

8. The optical waveguide structure according to claim 7, wherein: The cladding layer has a first inclined portion and a second inclined portion as the inclined portion, the first inclined portion being located at an end of the protruding portion in a third direction intersecting the first direction and the second direction, and the second inclined portion being located at an end of the protruding portion in a direction opposite to the third direction. The first inclined portion and the second inclined portion are located between the plurality of adhesives.

9. The optical waveguide structure according to claim 2, wherein: The waveguide layer includes a dummy layer arranged at a distance from the core layer in a direction intersecting the first direction and the second direction. The protrusion includes a portion located on a side of the dummy layer opposite to the first member.

10. The optical waveguide structure according to claim 9, wherein: The waveguide layer includes a first dummy layer and a second dummy layer as the dummy layers, wherein the first dummy layer is offset from the core layer in a third direction intersecting the first direction and the second direction, and the second dummy layer is offset from the core layer in a direction opposite to the third direction.

11. The optical waveguide structure according to claim 10, wherein: The dummy layer has a leakage portion that leaks light.

12. The optical waveguide structure according to claim 11, wherein: The dummy layer is provided with a shape that is a concave portion or a convex portion as the leakage portion when viewed in a direction opposite to the first direction at an edge portion of the dummy layer on the side opposite to the core layer.

13. The optical waveguide structure according to any one of claims 1 to 12, wherein: The thickness of the cladding layer stacked on the core layer in the first direction is 15 [μm] or less.

14. The optical waveguide structure according to any one of claims 1 to 12, wherein: The coating layer includes tetraethoxysilane.

15. The optical waveguide structure according to any one of claims 1 to 12, wherein: The width of the core layer in a third direction intersecting the first direction and the second direction is 1 [mm] or more.

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